Tag: header

nagle for TCP

Posted on by lechuck park

From Claude with some prompting
This image illustrates the TCP (Transmission Control Protocol) packet structure and the Nagle algorithm.

  1. Top section:
    • Shows data transfer between two computers.
    • Demonstrates how data (payload) is divided into multiple packets for transmission.
  2. Middle section – Packet structure:
    • Data Payload: The actual data being transmitted
    • TCP/IP header: Contains control information for communication
    • Ethernet header: 14 Bytes
    • IPv4 header: 20 Bytes
    • TCP header: 20 Bytes
    • Data + Padding: Actual data and padding added if necessary
    • MTU Limit: Maximum Transmission Unit limit
  3. Bottom section – Nagle’s Algorithm:
    • Normal TCP/IP transmission: Small data packets are sent individually
    • With Nagle’s Algorithm: Small data packets are combined into larger packets before transmission
    • Packet sending conditions:
      1. When an ACK is received
      2. On timeout
      3. When the TCP sending window overflows

The image effectively demonstrates the packet structure in TCP communications and explains how the Nagle algorithm improves network efficiency. The main purpose of Nagle’s algorithm is to reduce network overhead by bundling small packets together before transmission.

Anomaly IP Packet header

Posted on by lechuck park

From Gemini with some prompting
Title: Anomaly Detection (IP Packet Header)

Overview:

The image illustrates the structure of an IP packet header and how to detect anomalous activities based on TCP/IP header information.

Key Elements:

  • IP Address: Identifies the server.
  • TCP/UDP Port: Used to send and receive packets.
  • Service Port Number: Port number used to connect to a specific service.
  • Service Area: IP address range where a specific service is provided.

Indicators of Anomalous Activity:

  • Unknown IP: Packets coming from unknown IP addresses.
  • Foreign IP: Packets coming from overseas IP addresses.
  • Unused Port: Packets sent to unused ports.
  • TCP/UDP Port == 0: Packets with TCP/UDP port number 0.
  • IP/TCP Checksum == 0: Packets with IP/TCP checksum 0.
  • Unused IP Protocol: Packets using unused protocols.
  • Too Large (IP.ttl): Packets with excessively large TTL values.
  • Too Many (TCP Syn): Excessive number of SYN packets.
  • Too Many (IP. fragmented): Excessive number of fragmented packets.

TCP vs UDP

Posted on by lechuck park

From DALL-E with some prompting
This image explains how TCP provides reliable data transmission compared to UDP and underscores the reasons for this reliability. While UDP has a simple header structure utilizing basic port numbers and checksums, TCP includes additional fields in its header to ensure reliability. These supplementary fields encompass sequence and acknowledgment numbers for confirming data transmission and ordering, flags for connection state management, window size for flow control, and mechanisms for congestion control. The reliability of TCP is enabled through this complex header structure, with each field playing an essential role in ensuring accurate and dependable data transfer. Therefore, the reliability of all TCP communications is established through these specific fields in the header, emphasizing that TCP not just ‘enables’ reliability but ‘implements’ it in practice.